Emily in Paris star Ashley Park is talking about a recent scary medical ordeal in a new Instagram post. Sharing photos from her hospital stay, the Beef actress and cancer survivor wrote that what “started as tonsillitis spiraled into critical septic shock, which infected and affected several of my organs.” Park confirmed that her “health has improved despite what we had initially been told” and thanked her boyfriend, Emily in Paris co-star Paul Forman, as well as her medical team for aiding in her recovery.

What is septic shock, and how common is it to develop it after tonsillitis? Here’s what to know.

What to know about sepsis and septic shock

Septic shock begins as sepsis, which is “the body’s dysregulated response to infection,” says Dr. Justin Belsky, assistant professor of emergency medicine at Yale School of Medicine. While your immune system usually fights infections, in cases of sepsis, it can turn harmful and damage your own tissues and organs, causing inflammation throughout the body. According to the Centers for Disease Control and Prevention, 1 in 3 people who die in a hospital have sepsis during that hospitalization.

Septic shock is the most severe form of sepsis. It occurs when sepsis causes low blood pressure, and it can result in organ damage, respiratory distress and a slew of other health issues that can lead to death.

What causes sepsis and septic shock?

Sepsis is rare, but almost any infection can potentially lead to it. “Usually, people who are older or more immunocompromised, like cancer patients or patients who have an autoimmune disease or comorbidities, are more likely to develop sepsis,” says Belsky.

One risk of septic shock is the introduction of bacteria into the bloodstream, which is a potential risk of medical procedures. If a body’s immune response is unable to contain the infection caused by this bacteria, it can escalate, triggering septic shock.

What are the symptoms of sepsis?

Septic shock is very serious and potentially deadly, as the inflammation triggered by septic shock can lead to the dysfunction or failure of multiple organs, such as the heart, lungs, kidneys and liver. Severe respiratory failure may also occur. While studies have reported mortality rates ranging from 30% to 50% or higher, early recognition, administration of antibiotics and supportive care can help reduce this risk.

One of the tricky things about sepsis, which can escalate to septic shock, is that often the symptoms will mimic those of the flu. Look out for the following symptoms:

• Rapid heart rate

• Low body temperature or high fever

• Rapid breathing or difficulty breathing

• Confusion or altered mental state

• Cool and clammy skin

• Reduced urine output

• Nausea and vomiting

• Petechiae (small red or purple spots on the skin)

Knowing the symptoms of sepsis is vital. Timing is key for treatment, which can include fluids, antibiotics and source control, which may include surgery to remove the part of the body that is infected.

How rare is it to get septic shock from tonsillitis?

As of now, it’s impossible to say exactly what factors contributed to Park’s septic shock; typically, Belsky says, it is not common for tonsillitis to lead to septic shock. He notes that, while it’s very rare, in some cases a tonsillitis infection may not be able to clear a pocket of pus — a thick, yellowish or greenish fluid that forms at the site of infection or inflammation — that persists in the airway.

“Let’s say you had a surgery, and there’s a complication of the surgery that causes there to be pus,” he explains. “You may not clear that infection with just intravenous fluids and antibiotics until you remove the source of that infection. So if there’s a pocket of pus somewhere, it may need to actually be removed in order to clear the infection completely.” If the pus is not removed, Belsky says, the infection can persist, which can lead to sepsis and, later, septic shock.

It’s also possible for throat conditions like strep throat to lead to sepsis if not treated early with the use of antibiotics. However, this is rare.